Contemporary hard disk drives include an head stack assembly pivoting through an actuator pivot to position one or more read-write heads, embedded in sliders, each over a rotating disk surface. The data stored on the disk surface is typically arranged in concentric tracks. To access the data of a track, a read-write head is positioned by electrically stimulating the voice coil motor, which couples through the voice coil and an actuator arm to move a head gimbal assembly in positioning the slider close to the track.
Currently, a prior art actuator arm 52 tends to include an actuator notch 52Notch made from an actuator arm base 52Base coupling through a first actuator arm bridge 52A1 and a second actuator arm bridge 52A2, which join together to hold the swage site 52S as shown in FIG. 1A. Conventional wisdom dictates that the actuator notch is useful in reducing the mass of the actuator arm, which retaining sufficient rigidity to perform its purpose of holding a head gimbal assembly over a rotating disk surface to access a track.
There is a problem with this situation. When a mechanical shock is transmitted through the prior art actuator arm, it slowly decays, as shown in FIG. 2A. This is the kind of mechanical shocks experienced when a hard disk drive is bumped or dropped, a common phenomena, particularly in hand held devices such as portable music players, digital cameras, handheld computers and notebook computers. An improved actuator arm, no thicker than its contemporaries, is needed that can minimize actuator arm movement during mechanical shocks.